Specifications

Hawk 2XL Product Manual, Rev. B 63
9.7 Terminator requirements
Internal disc drive I/O termination (provided only in model “N” and “W” drives) consists of active circuits in an
LSI module that is permanently mounted on the PCB. All single initiator/single target (non-daisy-chain) applica-
tions require that the Initiator and disc drive be terminated. Daisy-chain applications require that only the units
at each end of the daisy-chain be terminated. All other peripherals on the chain must not be terminated. (See
Figure 10).
Note. Remove drive terminator enabling jumper TE (see Figure 7d) where terminators are not required.
Removal of terminator power source selection jumper TP (see Figure 7d) does not disconnect the ter-
minator resistors from the circuit.
It is highly recommended that ANSI SCSI-2 Standard’s Alternative 2 termination (active termination) be used
for applications with single-ended (“N”, “W” and “WC” models), especially if the bus will be operated at transfer
rates above 5 Mbytes/sec. The “N” and “W” models provides on-board active termination that can be disabled
by removal of the enable jumper TE (see Figure 7b).
Note. ACTIVE TERMINATORS ARE HIGHLY RECOMMENDED FOR USE IN THE DAISY-CHAIN AS
DESCRIBED ABOVE. ACTIVE AND PASSIVE TERMINATORS SHOULD NOT BE MIXED ON THE
SAME SCSI BUS.
“WC” models do not have terminators on the PCB. The user, systems integrator or host equipment manufac-
turer must provide a terminator arrangement external to the drive.
9.8 Terminator power
The drive may be configured to accept terminator power from pin 26 of the SCSI bus (on “N” and “W” models),
to supply power to the SCSI bus or to provide terminator power for internal termination circuits from the drive
power connector. See Figure 7d. The drive can provide power both to its own terminators and to the SCSI bus
terminator power line (Pin 26) if both “TP” jumpers are on.
SCSI devices providing terminator power (TERMPWR) shall have the following characteristics:
8-bit SCSI V TERM = 4.25 V to 5.25 V
800 mA min source drive capability
1.0 A maximum
16-bit SCSI V TERM = 4.25 V to 5.25 V
1500 mA min source drive capability
3.0 A maximum
The “WC” model drives cannot furnish terminator power, because no conductors in the 80 pin I/O connector
are devoted to terminator power.
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